Ultrasonic diagnostic apparatus

1. An ultrasonic diagnostic apparatus comprising: group setting means for setting a plurality of address groups with regard to a beam address array which corresponds to a three-dimensional echo data acquisition space, each address group corresponding to each partial space within the three-dimensional echo data acquisition space; sequence setting means for setting an iterative sequence of beam addresses, which is used for selecting a plurality of beam addresses constituting said beam address array wile selecting beam addresses repeatedly for each of said address groups; address selecting means for selecting the beam addresses in accordance with the iterative sequence which is set by said sequence setting means; beam forming means for forming an ultrasonic beam at a beam address selected by means of said address selecting means to thereby repeatedly form a set of ultrasonic beams for every partial space; and image forming means for forming an ultrasonic image which represents existence or behavior of an ultrasonic contrast agent within the three-dimensional echo data acquisition space based on echo data acquired by repeatedly forming a set of ultrasonic beams for every partial space.

2. An ultrasonic diagnostic apparatus according to claim 1 , wherein each of said partial spaces is composed of one or more scanning planes, and each of said scanning planes is composed of a plurality of ultrasonic beams which are sequentially formed in the electronic scanning direction.

3. An ultrasonic diagnostic apparatus according to claim 1 , wherein said image forming means uses two items of echo data obtained at the same beam address at a predetermined time interval, to form an ultrasonic image representing a change within said predetermine time interval.

4. An ultrasonic diagnostic apparatus according to claim 3 , wherein said image forming means includes a differential operation unit for executing a differential operation with regard to said two items of echo data.

5. An ultrasonic diagnostic apparatus according to claim 1 , wherein said beam forming means includes: a transducer unit having a one-dimensional array transducer for electronically scanning said ultrasonic beams; and a mechanical scanning mechanism for moving said transducer unit for mechanical scanning.

6. An ultrasonic diagnostic apparatus according to claim 5 , wherein said mechanical scanning mechanism moves said transducer unit for mechanical scanning in accordance with said iterative sequence.

7. An ultrasonic diagnostic apparatus according to claim 6 , wherein in the process of moving said transducer unit forward in the mechanical scanning direction, said mechanical scanning mechanism causes said transducer unit to move backward in steps.

8. An ultrasonic diagnostic apparatus according to claim 1 , wherein said beam forming means includes a two-dimensional array transducer, and said ultrasonic beams are electronically scanned two-dimensionally.

9. An ultrasonic diagnostic apparatus according to claim 1 , wherein said beam forming means performs scanning of said ultrasonic beams in the first scanning direction to form a scanning plane, and moves the position of said scanning plane forward in the second scanning direction, and in the process of moving the position of said scanning plane forward in the second scanning direction, such forward movement is repeated for each section corresponding to each of said address groups.

10. An ultrasonic diagnostic apparatus according to claim 1 , wherein said plurality of address groups are provided in a matrix with regard to said beam address array.

11. An ultrasonic diagnostic apparatus according to claim 10 , wherein each of said address groups is composed of a plurality of beam address lines, and ultrasonic beams are electronically scanned for each of said beam address lines.

12. An ultrasonic diagnostic apparatus according to claim 1 , wherein each of said address groups is composed of a plurality of beam addresses randomly provided in said beam address array.

13. An ultrasonic diagnostic apparatus according to claim 1 , wherein said beam address array is composed of a plurality of receiving beam addresses, and at each of said address groups, for one transmission and reception of said ultrasonic beam, one transmitting beam is formed and a plurality of receiving beams are concurrently formed.

14. An ultrasonic diagnostic apparatus comprising: a setting section for setting a plurality of address groups with regard to a two-dimensional beam address array which corresponds to a three-dimensional echo data acquisition space, each address group corresponding to each partial space within the three-dimensional echo data acquisition space; a sequencer for setting a sequence used for selecting a plurality of beam addresses constituting said beam address array while selecting beam addresses repeatedly for each of said address groups; an address controller for selecting beam addresses in accordance with the sequence set by said sequencer; a beam former for forming an ultrasonic beam at a beam address selected by said address controller to thereby repeatedly form a set of ultrasonic beams for every partial space; and an image forming section for forming an ultrasonic image which represents existence or behavior of an ultrasonic contrast agent within the three-dimensional echo data acquisition space based on echo data obtained by repeatedly forming a set of ultrasonic beams for every partial space.

15. An ultrasonic diagnostic apparatus according to claim 14 , wherein for each of said address groups, a step of sequentially selecting a plurality of beam addresses of the address group is repeated at least twice.

16. An ultrasonic diagnostic apparatus according to claim 14 , wherein said beam address array is composed of a plurality of receiving beam addresses, and for each of said address groups, a step of collectively selecting a plurality of receiving beam addresses of the address group is repeated at least twice.

17. An ultrasonic diagnostic apparatus for forming a three-dimensional echo data acquisition space within tissue of a living body in which an ultrasonic contrast agent is injected, said apparatus comprising: means for setting a plurality of partial spaces in said three-dimensional echo data acquisition space; means for effecting beam scanning with regard to said three dimensional echo data acquisition space by repeating transmission and reception of an ultrasonic wave plurality of times for each of said partial spaces; means for forming a partial image representing the existence or behavior of said ultrasonic contrast agent based on echo data obtained by transmitting and receiving an ultrasonic wave a plurality of times for each of said partial spaces; and means for synthesizing partial images regarding said plurality of partial spaces to form an ultrasonic image.

18. A two-dimensional ultrasonic beam scanning method for forming a three-dimensional echo data acquisition space within tissue of a living body in which an ultrasonic contrast agent is injected, said method comprising the steps of: determining a plurality of partial spaces with regard to said three dimensional echo data acquisition space; setting a sequence used for sequentially selecting said plurality of partial spaces while selecting each of said plurality of partial spaces a plurality of times; and two-dimensionally scanning an ultrasonic beam in accordance with said sequence, in which a set of ultrasonic beams is repeatedly formed in each partial space.